1. Field of the Invention
The present invention relates to novel cephalosporin derivatives, and a pharmaceutically acceptable salt, physiologically hydrolyzable ester and solvate thereof. This invention also relates to a process for their preparation, a use thereof as antibiotics, and a pharmaceutical composition containing the same derivatives as an active ingredient.
2. Description of the Prior Art
A number of cephalosporin compounds have been synthesized in which the cephem nucleus has a quarternary ammonium methyl at its 3-position and various acylamino groups at its 7-position. These compounds exhibit selective toxicity against bacteria only and present no substantial effects against animal cells. They have been widely used for the treatment of infectious diseases caused by bacteria as antibiotics having no substantial side effects. Thus, they are highly useful as drugs.
In recent years, an extensive investigation has been made to develop novel cephalosporin derivatives which have more potent antibacterial activities and a broad antibacterial spectrum, especially coupled with activities against cephalosporin resistant bacteria.
As a result, a number of cephalosporin derivatives have been developed which have a 2-(2-aminothiazol-4-yl)-2-substituted oxyiminoacetamido group as a side chain at 7-position and a fused pyridiniummethyl substituted at 3-position of the cephem nucleus. As prior art references which disclose such derivatives, U.S. Pat. No. 4,152,432 to Heymes et al.; U.S. Pat. No. 4,098,888 to Ochiai et al.; U.S. Pat. No. 4,258,041 to O'Callaghan; U.S. Pat. No. 4,748,172 to Katner; European Patent No. 0,318,552 to Katner; European Patent No. 0,164,944 to Bradbury; and European Patent No. 0,300,664 to Jung may be mentioned.
The present invention has been accomplished as an advanced improvement as compared with such investigation.
Thus, the object of the invention is to provide novel cephalosporin derivatives having strong activities and a broad antibacterial spectrum against both gram-positive and gram-negative bacteria, as well as excellent stability against .beta.-lactamase.